Young people taking nude pictures are contributing to a rise in sexual offences committed by children in England and Wales, police figures show.

Potential offenders were aged under 18 in more than half of all reported child abuse cases, according to analysis.

Senior officers say this abuse includes “exploratory behaviour” under-18s may not realise is illegal, and rape.

Police blame the rise on a combination of mobile phone ownership and the availability of hardcore pornography.

Ian Critchley, who leads the National Police Chiefs Council (NPCC) in tackling child abuse, said the new figures demonstrated the need for parents to have “uncomfortable conversations” with their children about the problem.

The study is the first of its kind carried out by the police Vulnerability Knowledge and Practice Programme, which has been analysing child abuse in England and Wales to help senior officers understand the threat to children.

According to the National Police Chiefs Council report, which looked at data from all 42 police forces in England and Wales:

The greatest risk to children remains abuse within the family. Police say this now accounts for around a third of child sexual abuse and exploitation, but can often be more severe.

Abuse by paedophile gangs, either on or offline, accounted for 5% of offences.

But police say they are dealing with a “growing and concerning trend” in the number of offences committed by children themselves. The most serious include rape and sexual assault.

A third category of offences involves indecent images of children, taken by children. Sometimes the subject has agreed, sometimes they have been coerced.

“It’s a crime to take, make, share or distribute an indecent image of a child that is under 18,” Ian Critchley said,”whether that’s in a consensual relationship or not.”

“It’s really important that young people understand that.”

“While they may be in a consensual relationship at that time, once that image is shared or unloaded onto a platform it’s lost.”

Images can be shared widely and used to blackmail the subject.

“That has huge consequences for the health and wellbeing of that individual.”

However dealing with offences by children requires police to make difficult decisions.

“The public wouldn’t expect us to criminalise young people which would have an impact on the rest of their lives, but it’s important we understand the totality of this to make sure the police response is right,” Mr Critchley said.

The NPCC believes young men are now growing up “three clicks away” from watching violent, abusive or even illegal videos on pornography platforms.

This, officers say, is encouraging them to adopt similar behaviour in sexual situations, or to demand videos and pictures from girls.

Senior police officers want the government, which is carrying out a review, to more tightly control access to pornography.

Susie Hargreaves, chief executive of anti-abuse charity the Internet Watch Foundation said these were crimes that could “happen in any family, to any child”.

“Having an internet connection and a webcam without supervision is like leaving a door open for the world’s worst predators to approach, speak to, groom and ensnare your children,” she said.